Assessment of shallow landslide susceptibility using the transient infiltration flow model and GIS-based probabilistic approach

This study proposes a probabilistic analysis method for modeling rainfall-induced shallow landslide susceptibility by combining a transient infiltration flow model and Monte Carlo simulations. The spatiotemporal change in pore water pressure over time caused by rainfall infiltration is one of the most important factors causing landslides. Therefore, the transient infiltration hydrogeological model was adopted to estimate the pore water pressure within the hill slope and to analyze landslide susceptibility. In addition, because of the inherent uncertainty and variability caused by complex geological conditions and the limited number of available soil samples over a large area, this study utilized probabilistic analysis based on Monte Carlo simulations to account for the variability in the input parameters. The analysis was performed in a geographic information system (GIS) environment because GIS can deal efficiently with a large volume of spatial data. To evaluate its effectiveness, the proposed analysis method was applied to a study area that had experienced a large number of landslides in July 2006. For the susceptibility analysis, a spatial database of input parameters and a landslide inventory map were constructed in a GIS environment. The results of the landslide susceptibility assessment were compared with the landslide inventory, and the proposed approach demonstrated good predictive performance. In addition, the probabilistic method exhibited better performance than the deterministic alternative. Thus, analysis methods that account for uncertainties in input parameters are more appropriate for analysis of an extensive area, for which uncertainties may significantly affect the predictions because of the large area and limited data.     

Coherent Flow Structures and Pollutant Dispersion in a Street Canyon

Boundary-Layer Meteorology - Coherent flow structures and pollutant dispersion in a spanwise-long street canyon are investigated using a parallelized large-eddy-simulation model. Low- and...     

Use of a forensic geochemical technique and a hydrogeological assessment to determine the source of petroleum hydrocarbon contamination at a foreshore site in Korea

Investigations undertaken in 2013 at a foreshore site that was historically used for ship repairs in Korea indicated that soil and groundwater were contaminated with petroleum hydrocarbons over an area of 10,000 m². Groundwater investigations and modelling were undertaken to determine the characteristics of aquifers beneath the site, including the direction and rate of groundwater flow and the extent of dispersion of total petroleum hydrocarbon contamination. To identify petroleum products residing in contaminated soils, the hump of an unresolved complex mixture on the baseline found in the data of gas chromatography was used as a new method. Based on objective facts obtained from basic investigation, the current state of contamination, and discrimination of oil species, the polluter as specified in the Korean Soil Environment Conservation Act was identified.     

Tracing solute infiltration using a combined method of dye tracer test and electrical resistivity tomography in an undisturbed forest soil profile

An accurate prediction of solute infiltration in a soil profile is important in the area of environmental science, groundwater and civil engineering. We examined the infiltration pattern and monitored the infiltration process using a combined method of dye tracer test and electrical resistivity tomography (ERT) in an undisturbed field soil (1 m × 1 m). A homogeneous matrix flow was observed in the surface soil (A horizon), but a preferential flow along macropores and residual rock structure was the dominant infiltration pattern in the subsurface soil. Saturated interflow along the slopping boundaries of A and C1 horizons and of an upper sandy layer and a lower thin clay layer in the C horizon was also observed. The result of ERT showed that matrix flow started first in A horizon and then the infiltration was followed by the preferential flows along the sloping interfaces and macropores. The ERT did not show as much detail as the dye‐stained image for the preferential flow. However, the area with the higher staining density where preferential flow was dominant showed a relatively lower electrical resistivity. The result of this study indicates that ERT can be applied for the monitoring of solute transportation in the vadose zone. Copyright © 2010 John Wiley & Sons, Ltd.     

Informing adaptation responses to climate change through theories of transformation

Transformative actions are increasingly being required to address changes in climate. As an aid to understanding and supporting informed decision-making regarding transformative change, we draw on theories from both the resilience and vulnerability literature to produce the Adaptation Action Cycles concept and applied framework. The resulting Adaptation Action Cycles provides a novel conceptualisation of incremental and transformative adaptation as a continuous process depicted by two concentric and distinct, yet linked, action learning cycles. Each cycle represents four stages in the decision-making process, which are considered to be undertaken over relatively short timeframes. The concept is translated into an applied framework by adopting a contextual, actor-focused suite of questions at each of the four stages. This approach compliments existing theories of transition and transformation by operationalising assessments at the individual and enterprise level. Empirical validation of the concept was conducted by collaborating with members of the Australian wine industry to assess their decisions and actions taken in response to climate change. The contiguous stages represented in the Adaptation Action Cycles aptly reflected the diverse range of decision-making and action pathways taken in recent years by those interviewed. Results suggest that incremental adaptation decision-making processes have distinct characteristics, compared with those used in transformative adaptation. We provide empirical data to support past propositions suggesting dependent relationships operate between incremental and transformative scales of adaptation.